GDF15 and thyroid cancer: In this study, we confirmed the applicability of six-marker genes (ADM3/HGD1/LGALS3/PLAB/TFF3/TG) for the distinction of benign and malignant thyroid tumours including follicular thyroid neoplasia with a sensitivity of 91%, a specificity of 100%, a positive predictive value (PPV) of 1.0 and a negative predictive value (NPV) of 0.94 (Krause et al, 2008).